Sanity check please! PHP/memcached strategy

[Dustin Sallings]

   Pipelining won't help when you're waiting for the response to one  
before sending a second request.

   Note that you'd also do 50 db requests with your current code.  The  
trick is to group them sensibly.

   After you find out what IDs you need, ask for them all at once.   
Figure out which ones you didnt get (set difference) and do a db query  
with an "in" clause for all of those at once.  Then set them  
individually back into the cache.

-- 
Dustin Sallings (mobile)

On Oct 26, 2007, at 16:03, mike <mike503 at gmail.com> wrote:

> I have the code below created and this has been my "scholastic"
> approach to adding in a cache layer seamlessly. by caching each row i
> have granular information that I can invalidate by creating an
> asset_set($entry_id) function and invalidating (and re-caching) the
> cache for that row.
>
> I know that people use this strategy (or at least part of it) with
> success. I've seen some code samples/explanations that map to this
> somewhat. However, am I still insane here, if the page has 50 assets,
> that is 50 memcached calls.
>
> Now I know some clients do request pipelining, in this case, would the
> PECL/memcache module issue 50 indivdual requests or be able to
> pipeline some into a few multigets grouped by the server?
>
> Any information is helpful. I'm trying to build this to scale from the
> start and want an appropriate caching strategy...
>
> function asset_get($entry_id) {
>        $key = "assets:{$entry_id}";
>        if(!$r = cache_get($key)) {
>                $q = db_query("SELECT individual_info FROM entries
> WHERE entry_id=$entry_id");
>                if(db_numrows($q) == 1) {
>                        $r = db_rows_assoc($q);
>                        cache_set($key, $r);
>                        return $r;
>                }
>        }
>        return $r;
> }
>
> function asset_list() {
>        $return = array();
>
>        $q = db_query("SELECT entry_id FROM entries ORDER BY  
> submitted DESC");
>        while(list($entry_id) = db_rows($q)) {
>                $r = coolstuff_get($entry_id);
>                $return[] = $r;
>        }
>        db_free($q);
>
>        return $return;
> }
>
> function asset_set($entry_id, $stuff) {
>        $key = "assets:{$entry_id}";
>        cache_del($key);
> ...      do the updates and stuff here. maybe issue an
> asset_get($entry_id) after to refill the cache with the updated info
> ...
> }
>
>